German encryption expert Karsten Nohl has deciphered and published the code used to encrypt most of world's cell phone calls. With the help of about 24 people, Nohl reproduced the GSM algorithm's code book, a vast log of binary codes that could be used to decipher mobile calls.
The 21-year old A5/1 privacy algorithm has been cracked before, but this is the first time that code has been published. Nohl says his goal is to convince cell phone operators to implement better security measures, but others fear that the publication of the code will make it a lot easier for criminal organizations to tap phone calls.
The action by the encryption expert, Karsten Nohl, aimed to question the effectiveness of the 21-year-old G.S.M. algorithm, a code developed in 1988 and still used to protect the privacy of 80 percent of mobile calls worldwide. (The abbreviation stands for global system for mobile communication.)
“This shows that existing G.S.M. security is inadequate,” Mr. Nohl, 28, told about 600 people attending the Chaos Communication Congress, a four-day conference of computer hackers that runs through Wednesday in Berlin. “We are trying to push operators to adopt better security measures for mobile phone calls.”